Sharp Kabushiki Kaisha Corporation

Koichi Oda

Yoshimitsu Inamori

Isamu Washizuka

Koichi Hatta

Shoichi Kawai

Katsuhiko Hashimoto

Yasuhiro Kotani

Toshihiko Sumitani

For display control of a liquid crystal display, display data and address signals for designating display dots are required. Segment address data designating X-direction addresses in the display space and common address data designating Y-direction addresses are input. Processing such as block transfer of address data in cases where the display address extends beyond the display space and where display picture is shifted within the display space has hitherto been carried out by software, but this places limitations on display speed. In the present application, the display space is divided in the X direction and the divisions of the display space are separately served by phural segment drive circuits. A common drive circuit is provided with hardware elements for selecting individual segment drive circuits so as to match the display address, This permits high-speed display operation and facilitates provision of software regulating the operation CPU.

Display control circuit including hardware elements for preventing

For display control of a liquid crystal display, display data and address signals for designating display dots are required. Segment address data designating X-direction addresses in the display space and common address data designating Y-direction addresses are input. Processing such as block transfer of address data in cases where the display address extends beyond the display space and where display picture is shifted within the display space has hitherto been carried out by software, but this places limitations on display speed. In the present application, the display space is divided in the X direction and the divisions of the display space are separately served by phural segment drive circuits. A common drive circuit is provided with hardware elements for selecting individual segment drive circuits so as to match the display address. This permits high-speed display operation and facilitates provision of software regulating the operation CPU.

In the case where a fed display data is to be displayed as it is, a display operation is executed in accordance with a predetermined first clock signal. In the case where a calculation operation is executed based on the fed display data and the calculation result is to be displayed as a display data, the display operation is executed in accordance with a second clock signal having a frequency higher than that of the first clock signal. In this way, the second clock signal is fed to a display device only when the calculation operation which requires a high speed processing is executed. Accordingly, power consumption can be reduced and an improved quality of display can be obtained. Further, an inversion signal is fed to the display device together with a display signal and a scan signal. The inversion signal is used for periodically switching the polarity of the display signal applied to the display device so as to prevent an occurrence that a direct current is applied to the display device. In the present invention, a first inversion signal and a second inversion signal having a frequency higher than that of the first inversion signal are switchably used. More specifically, in the case where there are relatively many displaying addresses on a column direction electrode, the second inversion signal is used.

Clocking method and apparatus for display device with calculation

A clock generation circuit (23) is provided for use with a data display device and a calculation unit, with the calculation unit performing a calculation in a calculation mode resulting in data which is displayed on the data display device. The clock generation circuit generates a first clock signal (CK2) and a second clock signal (CK1). The second clock signal (CK1) is generated by a circuit (52) only during a calculation mode. A clock switching circuit (54) selects, in dependence upon whether the calculation mode is being executed, between a clock signal (CKD) derived from the signal (CK1) and an independently-produced clock signal (CKI) for use as the first clock signal (CK2). Thus, power is conserved by turning off the circuit (52) during a pure display mode and by turning off an oscillator (24) which generates the signal (CKI) during a calculation mode.

A display integrated type position reading apparatus includes a display device driven for display in accordance with a driving signal in synchronization with a predetermined clock signal, and a conductive tablet mounted on a display screen of the display device. In operation, a CPU controls a tablet controller to apply voltage to the tablet. In response to a depression of an arbitrary position on the main surface of the tablet, the CPU reads out the depressed position as a digital signal via an A/D converter. The sampling by the A/D converter relating to reading is carried out at sampling points so as to avoid the mixing of noise, caused by a signal for driving the display unit, into the digital signal, resulting in an improvement in the read out accuracy of the depressed position.

Display integrated type position reading apparatus

A display control circuit includes a window coordinate data memory for storing window coordinate data which specifies a window region in a display region of a displaying device for displaying an image in accordance with address data and display data, a mask data generator for generating mask data for distinguishing the window region from the display region in accordance with the address data and the window coordinate data, and an operating device for generating display data input to the displaying device by operating the mask data and the display data corresponding to every address data input to the displaying device.

Display control circuit

An electronic calculator apparatus includes a keyboard for inputting numerical and function data, a printer for printing out on a record medium a sequence of data input by the keys and calculation results related to the data, and a printer controller for determining the content and format of the data printed out. The printer controller has the capability of recognizing when two successive function keys are actuated, and instructs the printer to print out on the record medium two successive function symbols without any numerical data symbols therebetween corresponding to symbols on the successively actuated function keys. Accordingly, an operator may study the record medium and locate amended function input data in regions where two function symbols ar juxtaposed.

Printer controller

A compact-size computer such as a functional calculator or a pocket computer selects either the sequential operation mode or formula memory mode according to the purpose of arithmetic operations and promotes faster and easier key operations. Specifically, it is substantially a calculator capable of executing formula calculations with different operational sequences wherein it comprises means for selecting and designating either the sequential operation mode that sequentially executes formula calculations according to individual key operations, or formula memory operation mode that executes operations after entry of the sequential operation mode.

Calculator or pocket computer with selectable operational sequence

A portable electronic computer or calculator is characterized in that it calculates a functional operation on the previously calculated result by simply actuating a function key switch while the result is being displayed. It is unnecessary to actuate any entry key switch. In a specific form of the present invention, the computer may calculate a functional operation on numerical data in response to input of a function command, the numerical data being either newly inputted or previously calculated.

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Sakai, Japan

Koichi Oda